We investigated the probiotic characteristics and anti-obesity effect of Lactiplantibacillus plantarum MGEL20154, a strain that possesses excellent intestinal adhesion and viability. The in vitro properties, e.g., gastrointestinal (GI) resistance, adhesion, and enzyme activity, demonstrated that MGEL20154 is a potential probiotic candidate. Oral administration of MGEL20154 to diet-induced obese C57BL/6J mice for 8 weeks resulted in a feed efficacy decrease by 44.7% compared to that of the high-fat diet (HFD) group. The reduction rate of weight gain was about 48.5% in the HFD+MGEL20154 group compared to that of the HFD group after 8 weeks, and the epididymal fat pad was also reduced in size by 25.2%. In addition, the upregulation of the zo-1, pparα, and erk2, and downregulation of the nf-κb and glut2 genes in Caco-2 cells by MGEL20154 were observed. Therefore, we propose that the anti-obesity effect of the strain is exerted by inhibiting carbohydrate absorption and regulating gene expression in the intestine.